While Crystal Singer is the first novel about Killashandra Ree, she originally appeared in short stories, which were rewritten into the novels. One short story, "Killashandra— Coda and Finale," tells of Killashandra's eventual mental deterioration, betrayal, and murder. While her future does not seem very bright, her story has been rewritten in Crystal Line (1992). While not considered her best novel, it is the last novel of the Crystal Singer series.

McCaffrey takes pains to tie her fictions together in a single universe through various hints and allusions. In Dragonsdawn (1988; see separate entry), McCaffrey identifies the Pern colonists as members of the Federated Sentient Planets (FSP), the result of Earth's extraterrestrial growth. In Killashandra, the galactic ruling body is also the FSP. The Ship Who Sang (1969) introduces us to Helva, the brain of a FSP ship, with various brawns/ humans as companions. In this novel, Killashandra leaves Optheria...